Department of Global Health and Population, Harvard School of Public Health, Boston, Massachusetts, USA.
PLoS Negl Trop Dis. 2010 May 25;4(5):e693. doi: 10.1371/journal.pntd.0000693.
Dar es Salaam has an extensive drain network, mostly with inadequate water flow, blocked by waste, causing flooding after rainfall. The presence of Anopheles and Culex larvae is common, which is likely to impact the transmission of lymphatic filariasis and malaria by the resulting adult mosquito populations. However, the importance of drains as larval habitats remains unknown.
Data on mosquito larval habitats routinely collected by the Urban Malaria Control Program (UMCP) and a special drain survey conducted in 2006 were used to obtain a typology of habitats. Focusing on drains, logistic regression was used to evaluate potential factors impacting the presence of mosquito larvae. Spatial variation in the proportion of habitats that contained larvae was assessed through the local Moran's I indicator of spatial association.
More than 70% of larval habitats in Dar es Salaam were human-made. Aquatic habitats associated with agriculture had the highest proportion of Anopheles larvae presence and the second highest of Culex larvae presence. However, the majority of aquatic habitats were drains (42%), and therefore, 43% (1,364/3,149) of all culicine and 33% (320/976) of all anopheline positive habitats were drains. Compared with drains where water was flowing at normal velocity, the odds of finding Anopheles and Culex larvae were 8.8 and 6.3 (p<0.001) times larger, respectively, in drains with stagnant water. There was a positive association between vegetation and the presence of mosquito larvae (p<0.001). The proportion of habitats with mosquito larvae was spatially correlated.
Restoring and maintaining drains in Dar es Salaam has the potential to eliminate more than 40% of all potential mosquito larval habitats that are currently treated with larvicides by the UMCP. The importance of human-made larval habitats for both lymphatic filariasis and malaria vectors underscores the need for a synergy between on-going control efforts of those diseases.
达累斯萨拉姆拥有广泛的排水网络，大部分排水网络水流不足，被废物堵塞，导致雨后洪水泛滥。伊蚊和库蚊幼虫的存在很常见，这可能会影响到由成虫蚊子传播的淋巴丝虫病和疟疾。然而，排水系统作为幼虫栖息地的重要性尚不清楚。
利用城市疟疾控制规划（UMCP）常规收集的蚊虫幼虫栖息地数据和 2006 年进行的专门排水调查数据，获得栖息地类型。重点关注排水系统，采用逻辑回归评估可能影响蚊虫幼虫存在的潜在因素。通过局部 Moran's I 空间关联指标评估含有幼虫的栖息地的空间变化。
达累斯萨拉姆超过 70%的幼虫栖息地是人为的。与农业相关的水生栖息地有最高比例的疟蚊幼虫存在，其次是库蚊幼虫存在。然而，大多数水生栖息地是排水系统（42%），因此，43%（1,364/3,149）的所有库蚊和 33%（320/976）的所有疟蚊阳性栖息地都是排水系统。与水流正常速度的排水系统相比，静止水中发现疟蚊和库蚊幼虫的几率分别是水流正常速度的 8.8 和 6.3 倍（p<0.001）。植被与蚊虫幼虫的存在呈正相关（p<0.001）。有蚊虫幼虫的栖息地比例在空间上是相关的。
恢复和维护达累斯萨拉姆的排水系统有可能消除目前由 UMCP 用幼虫剂处理的超过 40%的所有潜在蚊虫幼虫栖息地。人造幼虫栖息地对淋巴丝虫病和疟疾媒介的重要性突显了正在进行的这些疾病控制工作需要协同增效。
